Why and when did you become involved with NAS?
My friend, Fiona Farrell (former London Tonight presenter) has a son with autism and I've seen the difficulties he faces. I started attending its fundraising dinners three years ago.
Approximately how much time do you give to charities per year?
It's difficult to quantify because I often do phone interviews at work. Besides, I see it as time well spent creating awareness of the trek or charity.
What do you feel you bring to the charity?
I see this trek as an opportunity. The NAS press office has been superb, but I've also sorted things out and I'm happy to do as many interviews as I can.
Do you think celebrities do enough to promote charities?
On the whole they're very good because, however trite this sounds, they do have a privileged life and want to give something back. Guilt kicks in. Are there any other particular causes or organisations you support?
I'm an "Angel" for Action Against Addiction and I help Community Service Volunteers and the children's charity NCH.
What is the most annoying thing about being approached?
The element of moral blackmail which is sometimes hinted at.
If you want to go with Sian, call 020 7903 3531.